A disk file system, such as a RAID system, is used as a large volume data storage system of a computer center. FIG. 27 is a diagram depicting a prior art, FIG. 28 is a diagram depicting CKD format, and FIG. 29 is a diagram depicting a magnetic disk.
As FIG. 27 shows, a disk control apparatus (hereafter FCU: File Control Unit) 200 is connected to a host computer 100. A magnetic disk drive 210 is connected to the FCU 200. The RAID system is a system where a plurality of small capacity disks for a compact machine are used instead of an expensive disk for a large machine, and excels in the maintainability and redundancy of data.
The FCU 200 comprises CA (Channel Adapter) 220, CM (Centralized Module) 230, and DA (Device Adapter) 250, which are functional units having an MPU respectively, a magnetic disk drive 210, a memory for storing data to be used for functional control, cache memory 240, and a bus 260 connecting these components.
When an input/output request from the host 100 is received, the FCU 200, where data is held in the connected magnetic disk drive 210, develops data from the magnetic disk drive 210 to the cache memory 240 (staging operation), and executes all the input/output processing via the cache memory 240. However, if the target data is already on the cache memory 240 (cache hit) when the input/output request is received from the host 100, the FCU 200 reads/writes data on the cache memory 240, and notifies the end of processing to the host 100.
The FCU 200 is used for basic business (DB (Data Base) processing where data is updated corresponding to accounting and physical distribution) and information business (information search and processing), and is demanded to have higher speed and larger capacity since an exchange of even a larger volume of data is required.
In such a large capacity system, for each track of the magnetic disk drive 210 to be connected to the FCU 200, the CKD track format shown in FIG. 28 is used. As FIG. 29 shows, one disk 280 of the magnetic disk drive 210 has a plurality of concentric tracks. For example, one disk has about 10000 tracks.
All the tracks start with an index mark and end with an index mark. Each track is comprised of an HA (Home Address), an R0 (Record 0), and a user data record Rn (Records R1-Rn).
HA is a first block information of each track, and indicates the status of that track (e.g. normal, defective, replacement) and the physical position of the track. Records R0 and Rn are comprised of a Count Section (8 bytes), Key Section (0-255 bytes), and Data Section (0-47476 bytes). In the Count Section, such data as the length of the Key Section and length of the Data Section are stored. The Key Section and Data Section store the user data. The record R0 is comprised of the Count Section and Data Section, and such data as a replaced track address is stored in the Data Section.
This magnetic disk drive 210 is formatted to be the initial status where no user data exists when the FCU 200 is shipped or when the magnetic disk drive 210 is expanded, and is then used for actual operation. In other words, as FIG. 27 shows, the maintenance terminal (e.g. PC) 300 is connected at the factory or user location, and an initialization instruction is sent from the terminal 300 to the magnetic control apparatus 200. By this initialization instruction, the magnetic disk control apparatus 200 creates only HA and standard R0 (R0 is comprised of an 8 byte Count Section and a Data Section where all 8 bytes are 0) on each track.
Referring to FIG. 27, the conventional initialization (factory) format procedure will be described.
The maintenance terminal (e.g. PC) 300 issues a command to the CM 230, and instructs factory formatting of the magnetic disk drive 210 ([1]). The CM 230 receives the instruction from the maintenance terminal (e.g. PC) 300, schedules the tasks of the factory formatting, and instructs the DA 250 to execute the factory formatting ([2]). The DA 250 receives the instruction from the CM 230, and generates the factory shipment format, which is comprised of HA/standard R0 data patterns, in the internal buffer of the DA 250 ([3]). The DA 250 writes the data patterns generated in [3] to the magnetic disk drive 210 ([4]). Since factory formatting is executed for all the tracks on the magnetic disk drive 210, the DA 250 repeats [3]-[4] for all the tracks on the magnetic disk drive 210, and notifies completion to the CM 230 when completed ([5]). The CM 230 notifies the completion to the maintenance terminal (e.g. PC) 300.
In this way, factory shipment format data is directly written to each track of the magnetic disk drive 210 in a conventional factory formatting, so a large volume of data must be transferred to the magnetic disk drive 210, and formatting takes time. The magnetic disk drive positions the head on each track of the magnetic disk and writes format on each track, so it takes time to write formatting to all the tracks (e.g. 10000 tracks) of one magnetic disk.
For example, if factory formatting is executed for the mainframe type magnetic disk apparatus F6427H (made by Fujitsu), it takes 95 seconds for each drive (one disk drive). Also in a standard RAID system, many disk drives 210 are connected to one FCU 200, so if 64 magnetic disk drives are connected to one FCU 200, for example, then it takes 101 minutes. In the case of a normal user who connects magnetic disks of 64, 128 or 256 disk drives, it takes several hours at the factory or user location, which increases labor cost.